In the conventional paging system, each pager is assigned an identification number. In order for a caller to reach a particular pager, the caller dials a preassigned telephone number, which call is processed by a telephone company central switch, which in turn connects to the paging system clearinghouse. The central switch may be connected to the apparatus at the paging system by conventional lines or by telephone trunks. In either situation, the number of "lines", and hence, the number of pagers that may be served by the system is limited to the number of digits which may be processed by the central switch and the paging system. In the case of direct lines, the usual telephone number may be used as the unique identification number for the receiver. The drawback with the direct line system is the significant expense of dedicated lines and the limited number of dedicated lines which may economically be used between the central switch and the paging system clearinghouse/transmitter.
Another form of paging system uses trunk lines which do not technically have their own number, but which may transmit a collection of dedicated identification numbers, so long as the numbers are part of the same telephone exchange. Certainly, the use of trunk lines is preferable as trunk lines are considerably less expensive than dedicated lines and trunk lines can handle a greater number of calls.
In the case of a paging receiver which has more than four or five digits in its unique identification number, the use of trunk lines with direct inward dialing is not feasible, as known systems only allow transmission of up to five digits of a telephone/identification number, thereby effectively limiting the number of receivers in any one system to 100,000. In the case of a large metropolitan network, such limitation renders a system virtually useless. Certainly in the case of a system such as the one described in the Gaskill et al. reference, above, wherein nationwide, and possibly world-wide transmission to a particular receiver is possible, the limitation of a five digit identification number is unacceptable.
In the system described in Gaskill et al., a person (the caller) desiring to send a message to a particular receiver dials a telephone number, which may be either direct inward dialing on a trunk or have a dedicated line, and is connected with a central clearing house. Instructions are provided to the caller, by means of a voice response unit (VRU), which instructs the caller to dial the unique identification number for the particular receiver and, once the validity of the identification number is confirmed, instructions are provided to enable the caller to send a particular message. It is apparent that the caller must, in reality, dial two numbers instead of one, as is proposed in the instant invention.
Trunk interface modules are known in the art. One such module is the unit marketed by Syntellect Inc., under the Sceptre.TM., or the System 640 DID To Loop Start Interface manufactured by Gordon Kapes Inc. The specification and designs of such a system are described in the technical practice, issue Mar. 1, 1988 by Gordon Kapes Inc., which is incorporated herein by reference. Neither of the above described systems, however, provide any capability for passing a full seven digit telephone num therethrough to provide the number information to system components on the down-stream side of the interface module.